Using CSG Subtract or other options for cutting holes

(MadMaximus) #21

to tell you the truth, i like csh subtract, as long as you use it wisely.
I made a sewer system with a curved ceiling and had to join the tunnel from the street to it, and there was no other way that i could see to do it properly with csg. I could have made the entrance where they meet blocky… but i luv me angles… so i did the csg. ugly to look at in radiant, but clean as a whistle in game, all detailed brushes with caulk, only surface showing. 128x128x32 area that got the csg.

used wisely, its the only way to get certain angles. the clipper cannot do it properly, in the case that i did.

(Machine for to kill) #22

I rarely use subtract though I don’t think it’s as bad as people make it out to be (CSG merge is wonderful). I don’t think it’s as much a lazy mans tool as it is a tool for those who change their minds. The only times I’ve used it is when I decided to change the appearance of one of my buildings, and I decided to push the windows/doors inside the wall. I don’t want to sit there now and restructure everything because I changed my mind on something so I just use subtract, it does the job quickly and most of the time painlessly though you should check your resulting brushes.

This of course all refers to square brushes cutting into other square brushes, I don’t know why anyone would use subtract for polygons 5+ when a patch or bevel curve would do a much better job. I tried subtract with 5+ sided polygons when making a bunker and it made a mess ( to cut the part so you can see out, and put the mg). I used patches and I was done in about 2 min with much much better looking results.

(SCDS_reyalP) #23

MadMaximus, I suggest learning 3 point clipping. Subtracting complex shapes is asking for trouble. While I can’t say about your particular case, most people who think they use CSG subtract correctly are not. Usually, you can make a complex shape like you describe by creating one part of it with the clipper and edge edit, then cloning and rotating in 90 degree increments.

Machine for to kill,
Look at chavos picture…
Using CSG subtract to cut a square hole = more tris, overdraw, and z-fighting.
In other words, it is the lazy way of doing it. Of course you may find the higher r_speeds and z-fighting a worthwhile trade faster contstruction. That is entirely up to you.

(redfella) #24

I have yet to learn this. My assumption is that it just allows the user to clip in 3d versus just one single plane like 2-point. Is this right?

:chef:

(Machine for to kill) #25

Oh that’s nothing…you should try making 2 or 3 subtractions on the same wall surface. You get about 10 splits for each face. That’s why i said you need to look at your brushes and optimize after each such procedure. I don’t know why chavo says that you can’t miter the edges, I never had a problem doing this afterwards.

Subtraction works because it breaks up your brushes. Say I’ve made a 2 story house and then I need holes and breaks for my windows and such. I make subtractions and then I have all the neccessary brushes to make the house. Of course you don’t keep all those brushes, some you delete other you tweak a little bit so you get a nice and efficient result. It’s still faster than drawing every one of those brushes yourself. What subtract does for you is basically draw 4 brushes (technically 5 depending on depth) that preserve the dimenstions of the original structure, and require less time to tweak than drawing them all from scratch. So it does actually make for efficient construction.

(Telmo) #26

so let’s say you generated your terrain and now you want to cut the shape of your bunker in the mountain. How would you go about that?

(Blackadder_NZ) #27

Delete the terrain brush(es) where you’re going to build the bunker.

(Wils) #28

It varies - if you have any terrain brushes that are completely obscured by the building, delete them. Any that overlap you should really edge/vertex manipulate so they wrap around it. You can clip them into faces with multiple tris (in that it won’t break any blending on the terrain - ET is a lot more forgiving of that than RTCW), but it’s best avoided where possible.

(Wils) #29

On the subject of CSG Subtract, it’s completely evil and generally horrible to small children and animals. Every time you use it, god kills a domo-kun, or a kitten, or whatever. It’s bad, ok?

If we’ve ever used it in our maps it’s always due to time constraints or the designer in question roughing something out to get an idea of what he wants to create and then forgetting to clean it up afterwards. It’s never because it’s a good way of building your map.

(aaa3) #30

hm… after founding many threads on this topic with search, ive choosen this to post in my opinion. yea it says about holes, but i found the most good replies in this so decided in favour of this one.

i think its a very useful and good stuff. some even said he wishes it not to be in radiant :S everybody saying its evil. indeed when using with extreme shaped stuff or making a hole.
but think of terrain and other simple careful usage.
check attached small jpg - the bottom brush was made manually, and after lately discovered the substract tool i made the upper brush with it. no fragments, nothing unwanted artifact. and its less time than manually tweak the 3 vertices of each such brush to the bottom brush, as i did earlier. its by no way inferior nor had any disadvantages when using for this.
when u have brushes viewing in z axis the x,y plane they are exactly in cover, and the bottom have a custom upper face once made with hard work, the best way to attach a top brush to it with exacly touching bottom face is to use csg substract. i only discovered it after made by hand many others. it was a hard pain to make all the water brushes without it but after started using, quickly done the rest.
and i later used it in other places on my terrain instead of clip, not only this type of situations (exactly covered), and still worked fine. (yes!)
and also, it writes a report x fragments form y brushes. if x=1 y=1 then it done a good job, nothing worse than manual vertex editing. just my 2 cents

of course i dont use it to make holes, arches, et c. neither patches i use for these, i hate them. best way is to make from brushes manually, and then clip and/or vertex (face) edit. and yes i know 3 point clipping.

(kamikazee) #31

First of all: this a topic with a five-year old beard.

Second: CSG may sometimes do the right thing, but that doesn’t make it less evil. What you wanted to do there with the bottom/top brush is “tree-point clipping”.

You’d actually would only have made the prism structure as seen from the top, then split it into two with the clipper tool. I think that’s about as fast as the CSG substract method and it doesn’t leave traces. Of course, you’re free to build a map the way you want it - everyone uses what works for him.

(aaa3) #32

about that prism, yea your way is much better to make one of such a prism… , but when u adjust lots of items of that type, all side by side and their position are relevant to each other and has to make a global shape which u cant make in 1 try but have to always adjust it… then i guess for everybody its faster to make the bottom, adjust, and then make a fitting over-part. i cant imagine to use your method in this case, except if u wanna make all the pairs one after another. but then the tuning them to fit one’s need would be the nightmare.

what do you mean, it leaves traces? the invisible mini brush fragments? that means that i am wrong on assuming that if it reports no traces then it also in fact doesnt making them?

p.s. yea in some occasions it made evil results with me but then ctrl-z was useful, as always.